<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>弹性盒子</title>
    <style>
        .flex-container {
            display: flex;
            width: 300px;
            height: 250px;
            background-color: lightgrey;

            /* flex-direction: column; */
            /* justify-content: space-between; */

            /* flex-wrap: nowrap; */

            align-items: center;
            /* align-content: flex-end; */
        }
        .flex-item {
            background-color: cornflowerblue;
            width: 100px;
            height: 100px;
            margin: 10px;
        }
    </style>
</head>
<body>
    
    <div class="flex-container">
        <div class="flex-item">flex item 1</div>
        <div class="flex-item">flex item 2</div>
        <div class="flex-item">flex item 3</div> 
    </div>

</body>
</html>